Cushioning system for footwear

ABSTRACT

A midsole for footwear includes at least one solid or hollow cushioning tube positioned therein for improving the cushioning of the midsole. Preferably, the midsole includes a plurality of cushioning tubes fabricated of an elastomeric material. The tubes may vary in diameter and/or wall thickness relative to one another for varying the cushioning and stability characteristics of the system. Each tube may also vary in diameter and/or wall thickness along its length.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cushioning means for the midsole ofan athletic shoe, and more particularly, where the design of the devicecan be altered in such a way as to provide different amounts ofcushioning in different locations along the midsole of the shoe.

This invention relates to an improved footwear cushioning system. Inparticular, it is made from tubular shaped inserts located within themidsole of the shoe, for example, in the forefoot and/or heel areas.These tubular inserts provide a variance in the cushioning and stabilityof the midsole, and can be altered in such a way to provide specificcushioning, or if desired, more stability in specific locations.

Stability of an athletic shoe is very important in preventing therolling over of the foot, called pronation or supination. The cushioningmeans should not jeopardize the stability of the shoe. With the presentdesign, stability is not sacrificed and cushioning is enhanced.

In addition, there are distinctively different cushioning and stabilityneeds in different areas of the midsole of the shoe. The presentinvention is designed to provide the preferred amount of cushioning andstability to the midsole of a shoe in the forefoot and heel areas.

2. Description of the Prior Art

Footwear cushioning is one of the most important features of an athleticshoe where constant striking of the foot to the ground can causediscomfort and injury. There have been numerous designs to improvecushioning, most of which have focused on the materials below the footknown (in descending order) as the sock liner, insole, midsole, andoutsole. The first part directly below the foot is the sock liner, whichcan be made from a softer, more shock absorbent material like aresilient foam or elastomeric material. Below this is the insole, whichis a more firm platform to which the upper, consisting of fabric,leather, etc., is stitched. Directly below this is the midsole, which istypically the thickest portion and commonly uses a resilient foammaterial and therefore offers the most alternatives to cushioningtechnology. Finally, below the midsole is the outsole, which is theportion which contacts the ground and needs to be harder with a treadpattern to offer traction and durability.

An alternative midsole design is disclosed in U.S. Pat. No. 6,898,870 toKita, who describes a corrugated sheet inside the midsole which can varyin stiffness to provide varying cushioning and stability means. Thisdesign is limited in that it cannot vary the cushioning to particularareas, and is less effective in the forefoot area where the midsole isof a minimal thickness.

Another alternative cushioning means is described by U.S. Pat. No.6,898,870 to Rohde, who achieves cushioning by using columnar supportelements, each with an aperture to control the compliance or cushioningof each support element, with the option of using plugs inserted intothe apertures to further control the compliance of the support elements.This design is limited by the requirement of using these columnarsupport elements, which limit the direction of the cushioning andstability means to basically a vertical up and down action.

Still another alternative design for improving the cushioning of anathletic shoe is shown by U.S. Pat. No. 5,787,509 to Wu, who describes ashoe sock liner design which incorporates a resilient material with aplurality of cavities to provide shock absorption means. This design isagain limited by the thickness of the sock liner, which traditionally ismuch thinner than the midsole of a shoe.

The shoe cushioning system according to the present inventionsubstantially departs from the conventional concepts and designs of theprior art and in doing so provides an apparatus primarily developed forthe purpose of improved cushioning while maintaining stability as wellas improved appearance.

Therefore, it can be appreciated that there exists a continuing need foran improved athletic shoe cushioning systems. In this regard, thepresent invention substantially fulfills this need.

SUMMARY OF THE INVENTION

In view of the foregoing commonality inherent in the known types ofcushioning for footwear of known designs and configurations now presentin the prior art, the present invention provides an improved footwearcushioning system. As such, the general purpose of the presentinvention, which will be described subsequently in greater detail, is toprovide a new and improved footwear cushioning system which has all theadvantages of the prior art and none of the disadvantages.

There has thus been outlined, rather broadly, the more importantfeatures of the invention in order that the detailed description thereofthat follows may be better understood and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject matter of the claims attached.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of otherembodiments and of being practiced and carried out in various ways.Also, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of descriptions and should not beregarded as limiting.

As such, those skilled in the art will appreciate that the conception,upon which this disclosure is based, may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

The present invention provides a new and improved cushioning forfootwear which has all of the advantages of the prior art of knowndesigns and configurations and none of the disadvantages.

The present invention provides a new and improved cushioning forfootwear which may be easily and efficiently manufactured and marketed.

The present invention provides a new and improved cushioning forfootwear which is of durable and reliable construction.

The present invention provides a new and improved cushioning forfootwear which is susceptible of a low cost of manufacture with regardto both materials and labor, and which accordingly is then susceptibleof low prices of sale to the consuming public, thereby making suchfootwear economically available to the buying public.

The present invention provides a footwear cushioning system that canprovide specific stability means to various locations of the heel andforefoot areas.

The present invention provides an improved footwear cushioning systemthat can be adapted to athletic shoes for court sports as well as torunning and walking shoes.

Lastly, the present invention provides a new and improved cushioning forfootwear made with numerous tubes and/or rods inserted between twoportions of the midsole to provide desired cushioning and stabilitymeans in the heel and forefoot areas.

For a better understanding of the invention, its operating advantagesand the specific objects attained by its uses, reference should be madeto the accompanying drawings and descriptive matter in which there areillustrated preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of the lateral side of an article offootwear, constructed in accordance with the principles of the presentinvention.

FIG. 2 is an exploded view showing the various individual components ofthe footwear shown in FIG. 1.

FIG. 3 is an isometric view of the heel tubes.

FIG. 4 is an isometric view of the forefoot tubes.

FIGS. 5 a-d are detailed views showing the tubes varying in diameteralong their length.

FIGS. 6 a-d are detailed views of the tubes showing the variance of wallthickness along their length.

FIGS. 7 a-b are detailed views showing the tubes being solid for atleast a portion of their length.

FIGS. 8 a-b are detailed views showing the option of inserts beingplaced inside the tubes.

FIGS. 9 a-c are isometric views of various alternatives of tubeorientations to achieve different cushioning and stability means.

The same reference numerals refer to the same parts throughout thevarious Figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference now to the drawings, and in particular to FIGS. 1 through9 thereof, the preferred embodiments of footwear according to theinvention, generally designated by the reference numeral 10, will bedescribed.

The present invention uses pre-molded hollow tubes whose function is tovary the amount of cushioning of the shoe. The tubes, being circular oroval in cross section, are preferably fabricated using resilient plasticor elastomeric materials, and act as arches or springs to absorb theforce of impact. The amount of cushioning desired depends on thematerial, geometry, location, and orientation of each tube.

The material used for the tubes can vary the amount of cushioningachieved. For example, if a high degree of cushioning is desired, thenthe material should be an elastomeric grade material with a Shore Ahardness of 30-50 such as Thermoplastic Polyurethane(TPU), orThermoplastic Rubber(TPR), or Thermoplastic Elastomer (TPE). An examplewould be GLS Dynaflex. If less cushioning and more stability is needed,the material should be stiffer with a Shore A hardness value between50-90 such as Dupont Hytrel series or BASF Elastollan series.

The geometry and dimension of the tubes can vary to provide more or lesscushioning. For example, if more cushioning is desired, the diameter ofthe tube can be increased along with a reduced wall thickness toincrease flexibility to allow more compression of the tube duringimpact. If less cushioning is desired, the diameter of the tube can bedecreased, or the wall thickness of the tube increased in order toincrease the stiffness of the tube.

Where the tubes are located will also determine the amount ofcushioning. Within each of the heel and forefoot areas, there are manyoptions on where to locate each tube, as well as the number of tubes,the spacing between the tubes, the vertical positioning of the tubes,and the orientation of the tubes.

The orientation of the tubes will also affect the cushioning andstability of the shoe. For example, the tubes can be positioned 90degrees to the axis of the shoe to provide selective cushioning alongthe length of the shoe by varying the size, dimension, and stiffness ofeach tube. The tubes may also be oriented parallel to the axis of theshoe, or be positioned in a radial fashion in order to provide specificcushioning or stability in selected forefoot and heel areas.

The tubes are manufactured in a separate molding operation, prior tomolding the shoe midsole. Preferably, each tube will be injection moldedseparately in order to produce the exact geometry and materialproperties desired. High pressure injection molding can produce a verystrong and reliable structure which can withstand repeated impactloadings without breaking down and losing integrity, which is commonamong typical foam materials used in midsoles.

Once the tubes are molded, it can be positioned in the midsole one ofseveral ways. One option is to mold two separate portions of themidsole, one above and one below the centerlines of the tubes, each witha cavity molded in which is the exact shape of the portion of the tubesto be placed in the respective part of the midsole. In this example, thetubes are bonded to both the lower and upper midsole portions as theyare bonded to each other. This option provides the alternative of usingdifferent foam materials for each of the midsole portions. For example,using different densities or even using different materials where oneportion could be made with a lighter weight ethyl vinyl acetate(EVA)foam and the other portion comprised of a more dense and more durablepolyurethane(PU)foam.

A second option is to position the tubes in the opened midsole mold,then pour the premixed foam in liquid form into the mold, close the moldand the foam will expand and encapsulate the tubes. This requires anaccurate positioning of the tubes, for example using pins to locate thetubes in place, and then when the liquid foam is injected into the moldand begins to expand, the locating pins are retracted leaving the tubessuspended and accurately located within the midsole. With this method itis more economical but does not allow different density midsoleportions.

Using either the two piece midsole concept or the one piece midsoleconcept provides options on the vertical positioning of the tubes withinthe midsole. The tubes do not need to be centered within the verticalthickness of the midsole. The tubes can be positioned higher or lower asdesired within the midsole. In addition, the tubes can be positioned atan angle, for example, with the height of the tubes higher in the rearand lower toward the front of the shoe. Another option is to have thetube height vary from the medial side to the lateral side.

It is also possible to locate the tubes so they are outside the midsole.This would be most common in the forefoot area where the midsole is thethinnest, and there may not be space to embed tubes inside the midsole.There also may be advantages to locating the tubes on the upper side ofthe midsole in the heel area. When done this way, attention must begiven to the contour of the upper surface of the tubes so they are notfelt by the foot. In this case, the tubes could have a flatter,horizontal top surface or the sock liner and insole could have somerelief designed in the underneath side to accommodate the tubes.

The footwear cushioning system of the present invention provides aunique solution to footwear cushioning because the tubes act likesprings to absorb the force of impact. For example, when the heelstrikes the ground, the force of impact tends to compress the tubes,changing them from a circular cross section to an oval cross section. Indoing so, the outside walls of the tubes press against the foam, which,depending on its density and resiliency, can affect the amount ofcushioning provided.

In addition, the tubes do not need to be circular in cross section. Thetubes can be oval, with the major axis oriented either vertical orhorizontal or at an angle, to provide unique cushioning alternativesnever before achieved. With this option, the tubes can rotate as well ascompress to achieve desirable cushioning levels.

In addition, the tubes do not need to be cylindrical. The tubes can beconical or parabolic, meaning that the diameter changes in a nonlinearfashion along the length of the tubes. For example, the tubes could havea large diameter with a thicker wall near the outside of the shoe toprovide more stability and a more unique look to the shoe.

In addition, the tubes can accept inserts of various hardnesses, whichwhen placed in the tubes, can affect the amount of cushioning andstability.

In addition, the tubes can be solid or a portion of the tube be solid toprovide specific cushioning or stability characteristics as desired.

In addition, the tubes could be connected together, e.g., by a web, toform a cartridge. This would facilitate the molding and handling of thetubes, as well as positioning them in the midsole mold.

Furthermore, the tubes could act as a continuous air bladder, allowingflow between tubes to provide greater cushioning where needed.

Another advantage of the tube concept is aesthetics. The tubes can beopen ended at the edge of the midsole to provide maximum visibility, orenclosed inside a transparent material so debris doesn't collect insidethe tubes. The tubes can also be positioned like an automobile's exhaustpipes, with two tubes coming out of the rear portion of the shoe to givethe shoe a sports car look.

As mentioned before, the tubes can be molded individually and locatedseparately within the midsole of the shoe, or molded as aninterconnected cartridge. In either option, it is possible to vary thematerial, hardness, and geometry of each tube and along the length ofeach tube to achieve specific cushioning performance characteristics.

The footwear cushioning system of the present invention is not limitedto court sports shoes. It can be applied to running shoes, hiking shoes,walking shoes, and even dress shoes.

With greater reference to FIGS. 1 through 4 of the drawings, a firstembodiment of the present invention features elastomeric tubes 10connected by an optional web or strip 11 for improving the cushioning ofthe midsole in the heel area, and similar but thinner tubes 2 to improvethe cushioning in the forefoot area. The midsole is produced in twoportions: an upper portion 3 and a lower portion 4. The lower midsole isbonded to the outsole 5.

FIG. 2 shows an exploded view of the individual components of themidsole. The heel tubes 10 can comprise any number, and may or may notbe connected to one another. In the preferred embodiment, the heel tubes10 are comprised of four elastomeric tubes 10, and each tube is theexact width of the midsole so they are visible in the final product onboth the lateral and medial sides. The forefoot uses three solid tubes12 in the preferred embodiment. As used in the present specification,the term “tube” includes solid rods as well as hollow tubes.

In this case, preferably only the lateral side of the tubes 12 isvisible in the final product. Both the lower midsole portion 4 and uppermidsole portion 3 have cavities molded in with the exact shape of theportion of the embedded tubes. The assembly procedure is to apply anadhesive to the tubes and the midsole portions, then assemble togetherwith compression to form a complete midsole assembly.

FIG. 3 shows a detailed view of an alternative embodiment with the heeltubes connected to form a cartridge 1. In this embodiment, the wallthickness of the tubes is greater on the top side than on the bottomside. The tubes are also oval in shape and the major axis is oriented atan angle relative to vertical. In the cartridge 1 of FIG. 3, outside airis allowed to enter and leave the holes through the tubes 10. Inaddition, if desired, the strip 11 connecting the tubes can provide apassageway between adjacent tubes 10, so that air can pass between tubes10.

FIG. 4 shows a detailed view of an alternative embodiment of theforefoot tubes connected to form a cartridge 2. In this embodiment, thetubes 12 are solid forming rods to enhance the stability of this area.In addition, the tubes 12 are oval in cross section and their major axisis oriented at an angle similar to the heel tube cartridge 1.

FIGS. 5 a, 5 b, 5 c, and 5 d show examples of variations in tubediameters that are possible. It should be known that the amount ofoptions in tube diameters is numerous, and only limited by the thicknessof the midsole in that area.

FIGS. 6 a, 6 b, 6 c, and 6 d show examples of variations in wallthickness that are possible, where the broken lines depict the innerwall of the tube. It should be known that the amount of options in wallthickness is numerous, and only limited by the diameter of the tube inthat area.

FIG. 7 shows 2 examples of how the tubes vary between a hollow tube andsolid portion along their lengths, where the broken lines again depictthe inner wall of the tubes in the hollow portions. The amount of thetubular portion versus the solid portion can vary depending on thecushioning or stability desired in each area.

FIG. 8 shows examples of how inserts 14, 15 could be used to change theamount of cushioning and stability in the tubes. FIG. 8 a shows acylindrical insert 14 designed to insert into a cylindrical hole in thetube. Another option is shown in FIG. 8 b, where a conical shaped insert15 is designed to insert into a conical shaped hole.

Finally, FIG. 9 shows some examples of variations of tube orientation toachieve different cushioning amounts in different areas. There areunlimited options on how the tubes 10 a, 10 b, 10 c can be oriented. Forexample, in FIG. 9 c, the tubes 10 c run continuously the entire lengthof the midsole to provide cushioning everywhere. This design would bebest suited to a running or walking shoe, where the motion ispredominantly in a forward direction. FIGS. 9 a and 9 b show tubeorientations that would be best suited for motions in all directions.

As to the manner of usage and operation of the present invention, thesame should be apparent from the above description. Accordingly, nofurther discussion relating to the manner of usage and operation will beprovided.

With respect to the above description then, it is to be realized thatthe optimum dimensional relationships for the parts of the invention, toinclude variations in size, materials, shape, form, function and mannerof operation, assembly and use, would be evident to one skilled in theart from the foregoing description, and all equivalents to the examplesillustrated in the drawings and described in the specification areintended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of theprinciples of the invention. Further, since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the invention to the exact construction and operationshown and described, and accordingly, all suitable modifications andequivalents may be resorted to, falling within the scope of theinvention.

1. A footwear cushioning system comprising; A midsole which contains atleast one cushioning tube formed of an elastomeric material forabsorbing shock, wherein said cushioning tube is at generallyhorizontally oriented.
 2. The system as set forth in claim 1, whereinsaid midsole contains at least two tubes connected to one another toform a cartridge.
 3. The system as set forth in claim 1, wherein saidmidsole contains at least two cushioning tubes located in differentlocations.
 4. The system as set forth in claim 1, wherein the at leastone cushioning tube has a diameter that varies along its length.
 5. Thesystem as set forth in claim 1, wherein the at least one cushioning tubehas a wall thickness which varies along its length.
 6. The system as setforth in claim 3, wherein the at least two tubes vary in length relativeto one another.
 7. The system as set forth in claim 3, wherein the atleast two tubes have cross sectional shapes which differ from oneanother.
 8. The system as set forth in claim 1, wherein the cushioningtube has a solid portion along its length.
 9. The system as set forth inclaim 3, wherein the at least two cushioning tubes are oriented atdifferent angles relative to the longitudinal axis of the shoe.
 10. Thesystem as set forth in claim 1, wherein the cushioning tube has an outersurface which is sealed within the midsole and a hollow interior thatallows air or other fluids to pass through the tube.
 11. The system asset forth in claim 2, wherein said tubes are connected to one anotherwith a member that permits air to pass between said tubes.
 12. Thesystem as set forth in claim 3, wherein the midsole has across-sectional height, and the at least two cushioning tubes arelocated at different heights within the midsole.
 13. The system as setforth in claim 1, wherein the midsole has a top surface, and wherein thecushioning tube is located on the top surface of the midsole.
 14. Thesystem as set forth in claim 1, wherein the midsole has a bottomsurface, and wherein the cushioning tube is located on the bottomsurface of the midsole.
 15. The system as set forth in claim 1, whereinthe midsole is molded in two portions.